Process for the production of electrodes



Patented Aug. 16, 1927.

UNITED, STATES PATENT OFFICE.

PROCESS FOR THE PRODUCTION Oli ELECTRODES.

No Drawing. Application filed November 21 1925, Serial No. "70,676, ,and in Germany April 29, 1924.

My invention refers to electrodes and more especially carbon electrodes for .use inconnection with electric furnaces'or lamps and the like. It is an object of my invention to 5 provide means whereby electrodes are obtained which are more homogeneous and of a more uniform structure than similar electrodes hitherto produced.

With this and ether objects in view I will now describe the novel process in detail.

In the manufacture of electrodes as hitherto practised mostly tar, but in some cases alsopitch or a mixture of both is employed as a binder or agglutinant for the carbon.

1 In selecting the binder care must be taken to employ a substance or mixture which can be uniformly distributed in; the mass, for the better such distributionless agglutinant is required and the better the electrodes can be formed, pressed and freed of gases. It has been suggested, for instance, to liquefy the tar or pitch before admixing it to the carbon, in order to obtain a more-uniform distribution, however the results obtained were not satisfactory inasmuch as the molten pitch or the like does not mix sufficiently uniformly and intimately with the material to be agglomerated, lumps being formed so that a non-uniform structure results. Ifthe binders in question are comminuted by grinding, the powder obtained will be irregular as regards the size of the particles and moreover grinding is an expensive operation. p

I have now ascertained that an. excellent binder or agglutinant for use in t e manufacture of electrodes is obtained iftar, pitch, asphalt, resins, for instance the so-called acid resins, which ma be refined and may have been recovered in the distillation of 5 coal or petroleum, but also cumaron resins and the like are reduced to an impalpable powder, either by treating them in the air sifter or by atomizing the substances by means of spray nozzles, The impalpable powder thus obtained, which may have been cooled and dried previousl', can be mixed with the raw materials such as graphite, anthracite, baking coal, retort coal, soot,

60 half coke and the like duringits formation, so as to uniformly coat the single particles of the raw material with a thin layer of the agglutinant, the imfialpable powder leaving the air sifter or t e spray nozzle, instead can be effected, the

'tar lubricating oil of being collected as such, being directly admixed to the raw materials. I hereby obtain the advantage that by correspondingly adjusting the nozzle, if such nozzle is used for the atomization, I am in a position toex actly dose the quantity of agglutinant a'dmixed to the rawmaterials, so'that the agglomeration obtained, when subjecting the mixture to pressure, is a most perfect one, and less agglutinant can be used, while the mechanical strength of the electrodes thus obtained is superior to that of electrodes hitherto produced.

he invention offers the further advantage tlfat mixtures of different agglutinants can easily be used. Additions of other byproducts, such as for instance the anthracene residues resulting in the productihn of as well as crude naphtha: line and the like can be made to theaggluti nants proper, such as tar, pitch and the like. It has been found that in order to increase the binding power of the agglutinant it is preferable to add these residues such as anthracene or crude naphthaline directly to the fluid pitch tar and the like and to combine the mass, been removed by-means of suitable solvent, with the raw materials by spraying or atomization.

It has further been ascertained that it is also possible to subject all or part of the materials used in the productionof electrodes together to atomization by introducing t em into the mixing chamber under the action of compressed air. I wish it to be understood that I do not desire to be limited to the particular sub. stances nor to the exact details of operation above described for obvious modifications willoccur to a person skilled in "the art.

The term a glutinant as used in the claims isintended to cover tar, pitch, asphalt, residual or acid resins, cumaron or other resins and other suitable agglutinants either singly. or in any desired combination, I claim g I 1. The process'of manufacturing carbon electrodes comprisin I reducing an agglutinant to an impalpafile powder and admixing'sucli powder to the raw material from which the electrodes shall be formed. 7

2. The process ofmanufacturing carbon electrodes comprising reducing a mixture of from which the residues have an agglutinantand the other materials, from which the electrodes shall be formed, to an impalpable powder.

3. The process of manufacturing carbon 8 electrodes comprisin atomizing an agglutinant and then admixing same'to the raw material from which the electrodes shall be formed. I 4:. The process of manufacturing carbon 10 electrodes comprising atomizing a mixture of an agglutinant and the raw material,

from which the electrodes shall be formed, compressed air being used in such atomization.

5. The process of manufacturing carbon electrodes comprising atomizing an agglw tinant in such manner that the agglutinant in course of atomization is directly deposited on the raw materials from which the electrodes shall be formed.

. In testimony whereof I afiix my signature.

- EMIL KLEINSCHMIDT. 

